Synthesis of an Active Pharmaceutical Ingredient, Aspirin ( Including Raw Materials and Product Purity Checks )

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Date: 6/3/2012 Title : Synthesis of an Active Pharmaceutical Ingredient, Aspirin ( Including Raw Materials and Product Purity Checks ) Name: Class: Lab partners: Aim: The aim of this experiment is to prepare and recrystallise Aspirin, determine the percentage yield by mass of product, preform a test to check for phenols, and characterise it by its melting point. The following is the reactions scheme: Method: -[Lab Manual Pages 3, 4 & 5]- Results and Calculations: Compound Salicylic Acid Acetic Anhydride Aspirin Appearance White Powder Clear, Colourless liquid White Crystals Molar Mass (g/mol) 138g/mol 102g/mol 180g/mol Density if liquid (g/cm3) 1.08g/cm3 Weight used (g) 2.868g 5.4g N/A Moles used (mol) 0.0207mol 0.0529mol N/A Limiting Reagent   N/A Theoretical Yield of Products in moles N/A N/A 0.0207M Theoretical Yield of Product in Grams N/A N/A 3.726g • Calculations from table ^ : Moles of Salicylic Acid : Moles= Mass X Mr => M = 2.868 X 138 = 0.0207moles Moles of Acetic Anhydride : M = 5.4 X 102 = 0.0529moles Theoretical Yield in moles : moles of limiting reagent = 0.0207moles Theoretical Yield in Grams : Moles of limiting reagent X Mr of Product : = 0.0207mol X 180g/mol = 3.726g • Melting Points Compound Salicylic acid (raw material) Recrystallised Aspirin Expected MP Value 157-161oC 138-140oC Actual MP Value 158-160oC 137-139oC • Percentage yield: Percentage yield = 2.214/3.72 ₓ 100 = 59.52% => 60% • Test for phenols: Samples Crude Aspirin Recrystallised Aspirin Salicylic Acid Colour change of Samples + 1cmoC methanol Yellowish Yellowish Purple Inference Phenol not present Phenol not present Phenol Present Post- Practical Questions : Q1 What did your melting point indicate about the purity of your product? Explain your answer.

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